False dawn

The sky is full of optical phenomena that can make it tricky to get a clear view of the cosmos. These present a frustrating challenge to astronomers, but for astrophotographers they can provide a real feast for the eyes! This stunning image shows the centre of the Milky Way crossed by the eerie glow of zodiacal light, and is full of dust-induced features that obstruct scientific observations — but they look so beautiful it’s difficult to mind too much.

In this image, the centre of the Milky Way appears to be full of inky black gas. In fact, the dark swirling patches are simply the absence of visible light, because huge clouds of dust are obscuring the light from more distant stars. However, just as dust can give the illusion of darkness, it can also give the illusion of light. This is the case with zodiacal light, a fuzzy band of light that we see projected along the constellations of the zodiac. It is caused when sunlight is scattered by the disc of cosmic dust surrounding the inner Solar System. Particularly observant viewers may notice intricate structures within the band of light — notable here is the phenomenon of Gegenschein, the faint elliptical glow at the antisolar point towards the left of the frame. To the right, the bright column of zodiacal light, or “false dawn”, swells up from the horizon.

This image was captured over the course of a night and is the result of sophisticated imaging by ESO Photo Ambassador Petr Horálek, who sought to capture the structure of zodiacal light in a ground-based image like never before. It was taken at ESO’s La Silla Observatory in Chile. Petr Horálek won the title of "Czech Astrophotography of the Month" in January 2017 for his photo. The title is offered by the Czech Astronomical Society and the Czech Astronomical Institute.